We shall strive more particularly here below in this document to describe the problems and issues existing in the field of aircraft jet engines that have been faced by the inventors of the present patent application. The invention is of course not limited to this particular field of application but is of interest for any technique for the inspection of blades for turbomachines that have to face proximate or similar problems and issues.
The blades of jet engines, turbojet engines or again turbines are mechanical elements widely used for aeronautical applications. Their function is to transmit kinetic energy to a fluid (gas) when they are coupled with a motor, and thus to propel the aircraft.
A turbojet for example is generally formed by a set of blades working together on an axis of rotation axis and disposed in a plane appreciably perpendicular to this axis. The number of blades varies according to the applications.
During manufacture, the blades must be made with high precision in their dimensions or shape and they should be of constant and suitable quality.
It is therefore necessary to provide for dimensional inspection or controls for each of these components in order to ascertain that they are in truly in compliance with the requisite manufacturing tolerance values. Such inspection is generally performed on the production line and involves a certain number of dimensional characteristics.
A classic solution consists in inspecting these components when they come off the production line, either manually or by using automated dimensional inspection machines such as mechanical sensing machines. These machines are used to acquire the dimensions and a shape of a component and then to check it.
However, the visual inspection of the components responds neither to high production rates nor to quality requirements in aeronautics as defects remain difficult to identify with the naked eye.
Mechanical sensing solutions also require a discontinuous inspection process that needs relatively lengthy inspection time. In addition, propeller blades can have a relatively complex shape and profile making the inspection process difficult, calling for the use of separate machines to enable the inspection of all the dimensional characteristics of these components. In addition, present-day contactless inspection systems cannot be used to achieve the precision and production rates dictated by the manufacturing sector.
It would therefore be desirable to propose an automatic inspection machine capable of carrying out precise, reproducible and high-speed checks on all the dimensional characteristics of blades for turbomachines.